Modifying The Staton Gearbox For 5:1 Gear Reduction

The Staton gearbox has three gearshafts inside. The first connects to the engine's clutchdrum. That shaft's gear meshes with a 5:1 intermediate shaft which then meshes with the output shaft for an 18.75:1 gear reduction.

There is only one output shaft on the older-style gearbox, either on the inside or outside of the box. Then the updated gearboxes evolved with output shafts on the left side, right side, both sides AND where the 5:1 intermediate shaft locates.

Instead of buying a newer gearbox with the 5:1 output shaft, it would seem to be a simple matter to bore a 5/8" hole thru the gearbox left-sidecover. Then you just buy Staton's 5:1 intermediate shaft with 3/4" output shaft for the sprocket.

For that matter, you could bore the opposite side cover at the main output shaft, buy Staton's later-model output shafts and convert from one-side output to dual sprockets. Orrr, converting the outside drive gearbox to inside drive. You could also bore four holes in the left-side cover to remove the engine's mounting bolts. If you own an older-model Staton gearbox, you KNOW what a PITA it is to remove the engine.

In other words, upgrading and retrofitting to Staton's newer output shafts and options.

I had mulled over buying another gearbox with inside drive, especially while dreaming about a NuVinci conversion. This option is WAYYY cheaper than a new box, as the Staton's output shafts are only $29.95. His gearboxes sell for $240-$290.

On paper, it seems do-able. I want to tap off my Staton gearbox for 5:1 gear reduction to run my 100-watt miniature alternator. The dynamo puts out its power at 1,000rpm, so I need to gear it down from my engine's 8,000 rpm spins.

Well , today I asked the man himself, David Staton, if it was possible to retrofit his 5:1 output shaft onto one of his older model gearbox...

He said YES!!

As suspected, ya just have to drill thru the left-side cover and swap in his 16-tooth gearbox cog with extended shaft. No other parts needed except his $26.95 output shaft, and using the existing bearing.

Dave said it was a simple procedure, and he was not interested in selling his side covers.

Ah yes, a seal, answer is no. The bearing is sealed and and has an interference fit to the housing but not the shaft. If oil lubed, oil will leak between the shaft and inner bearing race, the reason Staton uses grease. I've mixed the Staton grease with a couple of ounces of 90w gear oil to thin it out a little. Seems to help keeping lube on the small cogs and I've seen no ill effects from lube in my clutch. DetonatorTuning wet lubed his box and I think it worked ok.